This is a 1990 technical information catalog from WISA for the 100 to 1000 series air pumps. WISA 300 air pumps were sold as an aftermarket updates to the ET-2 and 2.5 series of air bearing tonearms under the trade name “Airtech” along with a surge tank. We do not supply parts for these pumps. This catalog provides some technical and maintenance information for owners of the model 300 air pumps. Parts of the manual are omitted related to the 100,200, and 1000 series pumps.